package A;

import java.util.ArrayList;
import java.util.List;

public class T1 {

    public void T1(){
        System.out.println(111);
    }

    public static void main(String[] args) {
        Integer[] arr1 = new Integer[10];
        System.out.println(arr1[0]);   //null Integer

//        List<Integer>   list = new ArrayList<>();
//        System.out.println(list.get(0));   //  会报错 . 集合中没有初始化值

        int x=4;
        double y = x>4? 99.9 : 9;
        Object y2 = x>4? "99.9" : 9;
        System.out.println(y);
        System.out.println(y2);
     }
}
